inorganic: Not formed of living things or from the remains of living things crystal: A solid in which the atoms are arranged in a pattern that repeats again and again element: A substance composed of a single kind of atom compound: A substance in which two or more elements are chemically joined Mohs hardness scale: A scale ranking ten minerals from softest to hardest; used in testing the hardness of minerals streak: The color of a mineral's powder luster: The way a mineral reflects light from its surface cleavage: A mineral's ability to split easily along flat surfaces fracture: The way a mineral likes like when it breaks apart in an irregular way fluorescence: The property of a mineral in which the mineral glows under ultraviolet light
Outline
What is a Mineral?
geologist have already identified over 3,000 mineral
only 100 minerals are common
about 20 mineral make up earths surface
a mineral is an inorganic solid
a mineral always has a crystal structure
Naturally Occurring
minerals are not man made
Inorganic
mineral aren't made up of living things
since coal is made up of living things it is not a mineral
Solid
mineral must be solid
the particles must be packed together tightly
water is not a mineral since it is not solid
Crystal Structure
minerals need to have a crystal structure
crystal structures can sometimes be easy to identify but sometimes you can only identify it through a microscope
Definite Chemical Composition
a mineral always has certain elements in definite amounts
most minerals are compounds
a compound is a mineral that is made up of two or more elements combined
Identifying Minerals
in 1849, thousands of people went to California to find gold
few found gold, but many found minerals that look like gold
Hardness
to identify a mineral, finding the mineral's hardness is very useful
in 1812, Friedrich Mohs made the Mohs hardness scale
it ranks then minerals from softest to hardest
Color
it is easy to see what a mineral's color is
but a certain type of mineral can form in many different colors
Streak
the streak is the color of the mineral's powder
the color of the streak always stays the same color
Luster
minerals that look shiny is usually because they have metals inside them
Galena contains led and has a metallic luster
Malachite contains copper so it has a silky luster
Density
every mineral has its own density
the size doesn't change anything, its density will always stay the same
to compare the density you can lift 2 minerals that are the same size, one will probably weigh heavier
geologist measure the density of minerals by...
using a balance
place mineral in water to see how much water it displaces
dividing the mineral's mass by it volume
Crystal Systems
crystal structures are what kind of structure the atoms of the minerals grow into
there are six different structures so geologists seperate them into six different groups
crystals that grow in tight spaces are usually incomplete
crystal that grow in open spaces are almost perfectly complete
Cleavage and Fracture
identifying how a mineral breaks can help figure out what kind of mineral it is
a mineral that can break easily along flat surfaces have cleavage
have cleavage matters how the atoms in the mineral are arranged
if it is formed in a certain way, it'll be easier to break on one side than the other
most minerals don't split perfectly, this means the mineral is fractured
soft minerals have an earthy fracture
such as clay
rough minerals have an uneven fracture
Special Properties
minerals that glow under ultra-violet light have fluorescence
scheelite is fluorescent
some minerals contain magnetism
the mineral lodestone contains magnetism
a few minerals are radioactive
Uraninite can set off a Geiger counter
some minerals react chemically to acid
calcite will give off carbon dioxide if it touches vinegar
Table of Contents
4.1 Properties of Minerals
Vocabulary
inorganic: Not formed of living things or from the remains of living things
crystal: A solid in which the atoms are arranged in a pattern that repeats again and again
element: A substance composed of a single kind of atom
compound: A substance in which two or more elements are chemically joined
Mohs hardness scale: A scale ranking ten minerals from softest to hardest; used in testing the hardness of minerals
streak: The color of a mineral's powder
luster: The way a mineral reflects light from its surface
cleavage: A mineral's ability to split easily along flat surfaces
fracture: The way a mineral likes like when it breaks apart in an irregular way
fluorescence: The property of a mineral in which the mineral glows under ultraviolet light
Outline
What is a Mineral?
Identifying Minerals
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